This invention relates to a transport apparatus for handling cut products. More particularly, the invention relates to a transport apparatus for use with a saw which transversely severs multi-ply material such as logs of bathroom tissue and kitchen toweling and bolts of folded facial tissue and toweling.
In all present saws, the log or bolt is subjected to transverse cutting to develop a plurality of retail sized rolls or stacks. Also developed from the transverse cutting are two end trim pieces. These are present due to the log or bolt length being longer than an even multiple of the number of products cut therefrom. Co-owned U.S. Pat. No. Re. 30,598 describes a saw for cutting a log of convolutely wound paper tissue or toweling or a bolt of folded paper tissue or toweling. U.S. Pat. No. 3,572,681 describes a machine for producing bolts.
Typically, the cut product is carried in some fashion, with an interruption in the transport mechanism which corresponds to the trim locations. An example of a prior art apparatus for removing trims, while transporting cut product, is the belt and rail system which was based on the length-to-width ratio of the cut product.
The problem with the prior art, such as the belt and rail system, is that this type removed a high percentage of the trim pieces, but was not perfect. It was acceptable on the slower saws, with less automatic wrapping equipment. With higher speeds and more automation, the mechanical gripper finger style shown, for example, in U.S. Pat. No. 4,977,803 was used. The shortcomings with this unit are that the fingers are susceptible to breakage during jams, the fingers and cam followers are considered a high maintenance item, the finger roll diameter range is not always adequate, and the constant pitch (spacing) of the fingers requires that the incoming rolls are also on a constant pitch. This means that if the cutoff length is changed (a new roll pitch or length), the roll pitch between logs also changes, making the fingers end up out of phase with the rolls. The problem of phase differences due to changes in roll and/or log lengths has been addressed with drive train changes or the use of servo drives on the finger conveyor, but this has still not provided the solution desired by producers of these cut products.
The vacuum belts system (e.g., U.S. Pat. No. 5,458,033) addressed the problems of phasing for cut length and log length, and made for easier adjustment for roll diameter. But the vacuum system requires additional energy to run and moves air. The moving air creates noise that requires the use of a silencer and creates dust that requires a filter which needs regular cleaning, i.e., maintenance. The vacuum can also lift the tail end of the wound paper from the rolls and thereby adversely affect the tail seal.